[libcamera-devel] [PATCH v8 5/7] py: generate control enums from yaml

[Laurent Pinchart]

Hi Tomi,

Thank you for the patch.

On Fri, May 06, 2022 at 05:54:12PM +0300, Tomi Valkeinen wrote:
> Generate enums for controls from control_ids.yaml. The generator script
> has some heuristics to generate nicer enum names. E.g. instead of having
> "LensShadingMapMode.LensShadingMapModeOff" we get
> "LensShadingMapMode.Off". This heuristics may need to be updated when
> the yaml file is changed or new controls are added.
> 
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen at ideasonboard.com>
> Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> ---
>  src/py/libcamera/gen-py-control-enums.py  | 95 +++++++++++++++++++++++
>  src/py/libcamera/meson.build              | 12 +++
>  src/py/libcamera/pyenums_generated.cpp.in | 21 +++++
>  src/py/libcamera/pymain.cpp               |  2 +
>  4 files changed, 130 insertions(+)
>  create mode 100755 src/py/libcamera/gen-py-control-enums.py
>  create mode 100644 src/py/libcamera/pyenums_generated.cpp.in
> 
> diff --git a/src/py/libcamera/gen-py-control-enums.py b/src/py/libcamera/gen-py-control-enums.py
> new file mode 100755
> index 00000000..dcc28b1a
> --- /dev/null
> +++ b/src/py/libcamera/gen-py-control-enums.py
> @@ -0,0 +1,95 @@
> +#!/usr/bin/env python3
> +# SPDX-License-Identifier: GPL-2.0-or-later
> +#
> +# Generate Python bindings enums for controls from YAML
> +
> +import argparse
> +import string
> +import sys
> +import yaml
> +
> +
> +def find_common_prefix(strings):
> +    prefix = strings[0]
> +
> +    for string in strings[1:]:
> +        while string[:len(prefix)] != prefix and prefix:
> +            prefix = prefix[:len(prefix) - 1]
> +        if not prefix:
> +            break
> +
> +    return prefix
> +
> +
> +def generate_py(controls):
> +    out = ''
> +
> +    for ctrl in controls:
> +        name, ctrl = ctrl.popitem()
> +
> +        enum = ctrl.get('enum')
> +        if not enum:
> +            continue
> +
> +        if ctrl.get('draft'):
> +            ns = 'libcamera::controls::draft::'
> +        else:
> +            ns = 'libcamera::controls::'
> +
> +        cpp_enum = name + 'Enum'
> +
> +        out += '\tpy::enum_<{}{}>(m, \"{}\")\n'.format(ns, cpp_enum, name)
> +
> +        if name == 'LensShadingMapMode':
> +            prefix = 'LensShadingMapMode'
> +        else:
> +            prefix = find_common_prefix([e['name'] for e in enum])
> +
> +        for entry in enum:
> +            cpp_enum = entry['name']
> +            py_enum = entry['name'][len(prefix):]
> +
> +            out += '\t\t.value(\"{}\", {}{})\n'.format(py_enum, ns, cpp_enum)
> +
> +        out += '\t;\n'
> +
> +    return {'enums': out}
> +
> +
> +def fill_template(template, data):
> +    template = open(template, 'rb').read()
> +    template = template.decode('utf-8')
> +    template = string.Template(template)
> +    return template.substitute(data)
> +
> +
> +def main(argv):
> +    # Parse command line arguments
> +    parser = argparse.ArgumentParser()
> +    parser.add_argument('-o', dest='output', metavar='file', type=str,
> +                        help='Output file name. Defaults to standard output if not specified.')
> +    parser.add_argument('input', type=str,
> +                        help='Input file name.')
> +    parser.add_argument('template', type=str,
> +                        help='Template file name.')
> +    args = parser.parse_args(argv[1:])
> +
> +    data = open(args.input, 'rb').read()
> +    controls = yaml.safe_load(data)['controls']
> +
> +    data = generate_py(controls)
> +
> +    data = fill_template(args.template, data)
> +
> +    if args.output:
> +        output = open(args.output, 'wb')
> +        output.write(data.encode('utf-8'))
> +        output.close()
> +    else:
> +        sys.stdout.write(data)
> +
> +    return 0
> +
> +
> +if __name__ == '__main__':
> +    sys.exit(main(sys.argv))
> diff --git a/src/py/libcamera/meson.build b/src/py/libcamera/meson.build
> index e4abc34a..f4c7590c 100644
> --- a/src/py/libcamera/meson.build
> +++ b/src/py/libcamera/meson.build
> @@ -17,6 +17,18 @@ pycamera_sources = files([
>      'pymain.cpp',
>  ])
>  
> +gen_input_files = [
> +    meson.project_source_root() / 'src' / 'libcamera' / 'control_ids.yaml',
> +    'pyenums_generated.cpp.in'

You can add a comma at the end of the line. No need to resend for that,
it can be fixed when applying.

> +]
> +
> +generated_sources = custom_target('py_gen_controls',
> +                                  input : gen_input_files,
> +                                  output : ['pyenums_generated.cpp'],
> +                                  command : ['gen-py-control-enums.py', '-o', '@OUTPUT@', '@INPUT@'])
> +
> +pycamera_sources += generated_sources
> +
>  pycamera_deps = [
>      libcamera_public,
>      py3_dep,
> diff --git a/src/py/libcamera/pyenums_generated.cpp.in b/src/py/libcamera/pyenums_generated.cpp.in
> new file mode 100644
> index 00000000..96daf257
> --- /dev/null
> +++ b/src/py/libcamera/pyenums_generated.cpp.in
> @@ -0,0 +1,21 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2021, Tomi Valkeinen <tomi.valkeinen at ideasonboard.com>
> + *
> + * Python bindings
> + *
> + * This file is auto-generated. Do not edit.
> + */
> +
> +#include <libcamera/libcamera.h>
> +
> +#include <pybind11/smart_holder.h>
> +
> +namespace py = pybind11;
> +
> +using namespace libcamera;
> +
> +void init_pyenums_generated(py::module& m)
> +{
> +${enums}
> +}
> diff --git a/src/py/libcamera/pymain.cpp b/src/py/libcamera/pymain.cpp
> index 8c3be8f4..aff672aa 100644
> --- a/src/py/libcamera/pymain.cpp
> +++ b/src/py/libcamera/pymain.cpp
> @@ -131,10 +131,12 @@ static void handleRequestCompleted(Request *req)
>  }
>  
>  void init_pyenums(py::module &m);
> +void init_pyenums_generated(py::module &m);
>  
>  PYBIND11_MODULE(_libcamera, m)
>  {
>  	init_pyenums(m);
> +	init_pyenums_generated(m);
>  
>  	/* Forward declarations */
>  
> 

-- 
Regards,

Laurent Pinchart